What Happens to the Magnetic Field Outside of a Motor Coil?

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Discussion Overview

The discussion centers on the behavior of the magnetic field outside of a motor coil, particularly in the context of electric motors. Participants explore the nature of the magnetic field generated by the coil and its interaction with the surrounding environment, including the rotor and stator configurations. The conversation includes theoretical considerations and practical implications of magnetic field strength in different regions of the motor.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant notes that the magnetic field is not solely directed to the center of the motor but interacts with the rotor field, suggesting that the field's direction is influenced by the arrangement of the stator poles.
  • Another participant describes the magnetic lines of flux in a typical motor, indicating that they travel through the steel casing and alternate between north and south poles, minimizing the flux that strays beyond the motor.
  • A different perspective is offered regarding the interaction between the coil's magnetic field and the cylindrical field magnets, explaining that the combined effect creates a couple that influences the coil's rotation.
  • One participant raises a question about the strength of the magnetic field outside the coil compared to its strength at the center, asking whether the external field could be reused.
  • There is a query about the nature of the magnetic field along the length of the coil, specifically whether it exhibits a consistent north-south pattern or varies in strength.

Areas of Agreement / Disagreement

Participants express differing views on the nature and behavior of the magnetic field outside the coil, with no consensus reached on the strength or configuration of the field in relation to the center of the coil.

Contextual Notes

Some assumptions about the motor design and magnetic field interactions remain unaddressed, and the discussion does not resolve the mathematical or physical implications of the magnetic field behavior outside the coil.

crash_ndie
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hello sorry for the bad description I've always loved physics since i was in school so I've decided to start a project so please forgive my lack of technical wording and ignorance i promise am a quick learner lol

on a motor we use electricity / current passed though a coil to create a magnetic field focused down the center of the motor to make it spin.

My question is what happens to the field out side of the coil.

(wish could post a pic be so much easier to ask my question)

if the field in the center of the motor is , say 10 as its maximum what will it be on the out side of the coil ?
 
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crash_ndie said:
on a motor we use electricity / current passed though a coil to create a magnetic field focused down the center of the motor to make it spin.
Hi crash_ndie. Welcome to Physics Forums.

I wouldn't exactly agree that the field is directed to the centre of the motor; the stator field is directed to where it will best interact with the rotor field.
My question is what happens to the field out side of the coil.
I think you'll find in a typical motor that each pole is firmly bolted to the steel case of the motor, and poles alternate around the casing, N, S, N, S, and so on. So the magnetic lines of flux travel via the steel casing around to the adjacent poles to reenter the motor through the pole face of the adjacent poles. That way, very little flux strays beyond the motor.
 
crash_ndie said:
on a motor we use electricity / current passed though a coil to create a magnetic field focused down the center of the motor to make it spin.

My question is what happens to the field out side of the coil.

(wish could post a pic be so much easier to ask my question)

if the field in the center of the motor is , say 10 as its maximum what will it be on the out side of the coil ?

In a DC motor , when current flows in the coil, the magnetic field of coil interacts with the magnetic field of cylindrical field magnets , due to the combined effect , the coil is acted upon by a couple. The field is linked with the coil and another one is linked with cylindrical field magnets. At the centre of coil the effect of magnetic field is zero. They appear to be in same direction. Hence there are these two system of magnetic fields.

They are maintained constant. When coil plane comes at right angles to the plane of magnetic field of cylindrical magnets , the effect is zero but due to angular momentum it continue to rotate. After 180 degrees the split rings reverse and it continue its process like this, clockwise or anticlockwise.
 
say we base the motor on this type were the coil is out side and the rotor is in the center
see attatched pic..

on the second pic (best i could find to show the field) picture the magnet as the spining motor C & D.

on the field A, E & B what's happening to the field in relation to north and south, dose it flux n,s,n,s,n,s up the length of the coil to the center of the motor, Or is it a constant n,s to the center of the coil.

basically What am trying to find out, is the field as strong on the out side of a coil as it is in the center of the coil. Could this spare magnetic field be re - used
 

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